You have no idea how BADLY I want to read all of your post, but I'm lazy at the moment.

Also I love this thread too.

What I can add so far just from skimming the posts is that I felt like I may have played on the edge of a little to immature for Oakey when I started. Was I RPing him more like a 7 or 8 year-old as opposed to 11? Maybe I'm not sure (I'll have to go back and look up my first RPs as him...which may be painful to read). Although what I can say about this in general is that while some kids at that age may be above their grade level others, like myself may have had learning disabilities and needed the extra push to pass their classes. I'm not saying we should suddenly begin making some of our students dyslexic, or have ADHD to be more realistic but we should also consider the other side where some aren't as learned as the others.
Oakey was Muggleborn, but was brought up in a Pureblood household so he knew more than most Muggleborns when he started. It could be used in another way. Where a Pureblood might have had something that held him/her back from understanding 'What is Magic and why does it do what it does.'

As for Model choosing. I'm not sure why I chose who I chose for Oakey, but I'm glad I did. I shaped a lot of his personality around the appearance.